Technical Field
The present invention relates to a method for manufacturing a light distribution member, and to a method for manufacturing a light emitting device.
Description of the Related Art
Light emitting devices having light emitting diodes or other such light emitting elements have been used in recent years as the light source for automotive headlights. With a light emitting device used in automotive headlights, a plurality of light emitting elements are arranged on a single substrate, and wavelength conversion members containing a fluorescent material are disposed on these light emitting elements (see JP 2012-119407A and JP2012-527742A, for example).
With a light emitting device such as this that has a plurality of light emitting elements, however, when the individual light emitting elements are controlled to be lit separately, if there is an unlit light emitting element adjacent to a lit light emitting element, light may leak out from the lit light emitting element, and there may be a minute amount of light-emission from the unlit light emitting element.
To prevent this light leakage, a method has been proposed in which a reflective resin containing titanium oxide is disposed between adjacent wavelength conversion members. To form the reflective resin, however, there has to be enough space between the wavelength conversion members. This space contributes to a darkening of the field of the light emitting elements when adjacent light emitting elements emit light simultaneously.
There is also a method in which a flat wavelength conversion member is diced into smaller pieces, after which a light blocking film composed of a metal film or a dielectric laminated film is formed on the side faces of these wavelength conversion members. However, the side faces produced by dicing have an uneven surface, which means that the light blockage or reflecting effect is not adequately obtained. Furthermore, it is not easy to control the thickness of the metal film or dielectric laminated film formed on the side faces, and it is difficult to form a uniform film on the side faces.
Also, there has been a proposal in which finely-processed triangular prisms made from silicon are disposed between adjacent light emitting elements, and the side faces of the wavelength conversion members corresponding to the individual light emitting elements are coated with silver paste, which prevents light from leaking out from adjacent light emitting elements (see JP 2012-169189A, for example).
However, since numerous light emitting elements are arranged in a row or a matrix in the light emitting devices used in automotive headlights, not only do a step of disposing triangular prisms between individual light emitting elements, a step of coating the side faces of the wavelength conversion members corresponding to the individual light emitting elements with silver paste, and so forth require sophisticated processing technology, but the manufacturing process may be made more complicated.